1. Field of the Invention
The present invention relates to an improvement of a differential device comprising: a differential gear mechanism; and an integrated differential case housing the differential gear mechanism, the differential case including first and second bearing bosses formed integrally on one side portion and another side portion of the differential case and aligned on a same axis to be rotatably supported by a transmission case; a work window for inserting the differential gear mechanism, the work window being provided in a peripheral wall of the differential case; and a pair of sleeves fitted and inserted to the first and second bearing bosses from outer end sides thereof and respectively connected to a pair of left and right side gears of the differential gear mechanism, wherein oil seals are to be set between outer end portions of the sleeves which protrude from the first and second bearing bosses and the transmission case, and left and right drive shafts are to be fitted and inserted into the sleeves and to be spline-fitted to hubs of the pair of side gears.
2. Description of the Related Art
Such a differential device is known as disclosed in Japanese Patent No. 3751488 and Japanese Patent Application Laid-open No. 2013-72524.
In the above-described differential device, after the differential gear mechanism including the side gears is incorporated into the integrated differential case through the work window, the sleeves are fitted and inserted into the first and second bearing bosses from the outside to be spline-fitted to the side gears. In other words, if the side gear and the sleeve are integrated, a total length thereof becomes longer than an inside diameter of the integrated differential case, and the side gear and the sleeve cannot be incorporated into the differential case.
In the above-described conventional differential device, the sleeve is fastened to the side gear by pressure welding or fusion welding to prevent lubricating oil in the differential case from leaking out of a space between the side gear and the sleeve. However, during assembly, a special process such as pressure welding or fusion welding is an obstacle to improving efficiency of assembly.